Abdullah

iTrader: (2)

for the 398 LT1 you have go with a 58mm TB and even a monoblade TB if you can. throttle body size doesn't hurt the motor's performance and even ported intake manifold doesn't hurt, it is the heads that have been over-ported will hurt performance.

but you have to tune after you install either the 58mm TB or the monoblade TB.

jarretthise

iTrader: (9)

and i would assume you could be making a little more power if you had your intake ported and polished to 58mm!! i could be wrong, dont know what setup your running so.

as for your ? though i would have to say 58mm...thats the logical way to go..

slomarao

iTrader: (6)

id say 58mm. monoblade if you have big plans/deep pockets.